4,4′-Dimethylazobenzene as a chemical actinometer

Casimiro, Lorenzo; Andreoni, Leonardo; Groppi, Jessica; Métivier, Rémi; Silvi, Serena

doi:10.1007/s43630-021-00162-3

Cited by 5 publications

(2 citation statements)

References 57 publications

(88 reference statements)

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“…DMAB has been recently introduced as a reliable chemical actinometer to conveniently quantify the photon flux in the UV–vis region of the light spectrum. [ 29 ] Figure S7a, Supporting Information, shows the in situ monitoring of the DMAB photoisomerization reaction performed at different LED output powers. Figure S7b, Supporting Information, presents the calculated photon flux absorbed by the solution in the microreactor at different LED output powers.…”

Section: Resultsmentioning

confidence: 99%

Accelerated Photostability Studies of Colloidal Quantum Dots

Morshedian

Abolhasani

2023

Solar RRL

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Photostability of colloidal quantum dots (QDs) is one of the major criteria determining their long‐term applicability in energy and chemical technologies. Yet, photostability studies of QDs are extremely sensitive to experimental conditions, lack a detailed mechanistic understanding, and are time‐, material‐, and labor‐intensive. Herein, an automated microfluidic platform for accelerated photostability studies of colloidal QDs is introduced, 3.5× faster and 100× more material efficient than the conventional flask‐based studies. The developed microfluidic strategy provides real‐time in situ access to the optical properties of QDs throughout the photostability experiments. Specifically, the material‐efficient microfluidic platform is used to study the mechanism and kinetics of CdSe QDs' photodegradation. The studies suggest that a generation of singlet oxygen via triplet energy transfer from colloidal CdSe QDs can initiate photo‐oxidation of CdSe QDs. Furthermore, the presence of at least one additional photodegradation pathway of CdSe QDs parallel to the photo‐oxidation pathway is unveiled. The systematic photostability experiments reveal how the incident photon flux and the starting average diameters of CdSe QDs affect their photodegradation rates. This work sheds light on the complex and multifaceted photodegradation phenomena of colloidal CdSe QDs and illustrates the unique characteristics of microfluidic strategies to improve and accelerate photostability studies of QDs.

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Section: Resultsmentioning

confidence: 99%

Accelerated Photostability Studies of Colloidal Quantum Dots

Morshedian

Abolhasani

2023

Solar RRL

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“…Potassium ferrioxalate [ 39 – 40 ] is one of the most used actinometers while also some azobenzene derivatives have been reported as reaction quantum yield standards [ 11 , 22 ]. Although new chemical actinometers are being proposed [ 41 – 42 ], actinometry is dependent on quantum yields determined decades ago [ 10 , 43 ]. Using chemical actinometers is often labor-intensive, and measurements are restricted to irradiation wavelengths where the actinometer absorbs.…”

Section: Introductionmentioning

confidence: 99%

A fiber-optic spectroscopic setup for isomerization quantum yield determination

Volker,

Steen,

Crespi

2024

Beilstein J. Org. Chem.

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A spectroscopic setup for isomerization quantum yield determination is reported. The setup combines fiber-coupled LEDs, a commercially calibrated thermopile detector for measurement of the photon flux, and a fiber-coupled UV–vis spectrometer. By solving the rate equations numerically, isomerization quantum yields can be obtained from the UV–vis absorption spectra. We show that our results for the prototypical photoswitch azobenzene are in excellent agreement with the literature. The analysis of the errors showed that the quantum yields determined using this method are in the same order of magnitude as when using actinometry, thus demonstrating the reliability of our setup.

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Optically Controlled Recovery and Recycling of Homogeneous Organocatalysts Enabled by Photoswitches

et al. 2023

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We address a critical challenge of recovering and recycling homogeneous organocatalysts by designing photoswitchable catalyst structures that display a reversible solubility change in response to light. Initially insoluble catalysts are UV‐switched to a soluble isomeric state, which catalyzes the reaction, then back‐isomerizes to the insoluble state upon completion of the reaction to be filtered and recycled. The molecular design principles that allow for the drastic solubility change over 10 times between the isomeric states, 87 % recovery by the light‐induced precipitation, and multiple rounds of catalyst recycling are revealed. This proof of concept will open up opportunities to develop highly recyclable homogeneous catalysts that are important for the synthesis of critical compounds in various industries, which is anticipated to significantly reduce environmental impact and costs.

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4,4′-Dimethylazobenzene as a chemical actinometer

Cited by 5 publications

References 57 publications

Accelerated Photostability Studies of Colloidal Quantum Dots

Accelerated Photostability Studies of Colloidal Quantum Dots

A fiber-optic spectroscopic setup for isomerization quantum yield determination

Optically Controlled Recovery and Recycling of Homogeneous Organocatalysts Enabled by Photoswitches

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